The invention relates to a stator for an electric drive motor having a number of stator teeth which are separated by slots and having a multiple-section winding, with one section comprising a plurality of coils and with individual coils each surrounding a plurality or teeth. Slotted stators for electric drive motors having a number of symmetrical stator teeth and a multiple-section three-phase winding are known.
One example of a known stator is described in German patent application DE 198 38 335 A1. The stator described in the cited document has a number of stator teeth, which are separated by slots, and a multiple-section winding, which in particular may be in the form of a three-phase winding. In this case, one section comprises a plurality of coils and individual coils each surround a plurality of teeth, with a plurality of stator teeth in each case being combined to form one stator tooth with a plurality of tooth heads.
As is known, the efficiency of a stator is governed essentially by its slot filling, that is to say the total conductor cross section with respect to the total area of the stator.
The stator according to the invention for an electric drive motor has a number of stator teeth separated by slots; in this case, the stator teeth have a multiple-section winding wound around them. A section comprises a plurality of coils, and individual coils each surround a plurality of teeth. In this case, two teeth are in each case combined at the level of their tooth neck to form a combined stator tooth. The advantage of this measure according to the invention is better utilization of the physical volume by a novel arrangement of the winding area created by the described configuration of the stator teeth, while ensuring that the stator according to the invention can be wound using the existing winding technologies (flyer, pull-in, bar and needle-winding techniques). This measure leads to an improvement in performance and to a reduction in the size of the electric motor equipped with the stator according to the invention, thus making it possible to save material and to achieve a better power-density/cost ratio.
One advantageous variant of the invention consists in that each stator tooth is wound around, and/or both the tooth feet and the tooth heads are wound around.
Furthermore, it is advantageous if a coil in each case surrounds two tooth heads of adjacent teeth, and in each case one tooth foot is surrounded by a further coil. In this case, it has been found to be expedient if the stator teeth are designed in such a manner that the coils around the tooth feet and the coils around the tooth heads have similar parameters to, for example, a similar flux chain.
In a further advantageous embodiment of the invention, only combined teeth are located on the stator circumference.
A further variant of the invention consists in that coils, through which current flows for one phase at the same time, of adjacent teeth are wound in opposite senses.
The capability to wind the stator according to the invention can be enhanced in that stator teeth with a first and a second geometric shape are arranged alternately on the stator circumference, such that asymmetric slots are formed between the stator teeth. In this case, it has also been proven advantageous for the tooth feet on one of the two geometric shapes not to have coils wound around them.
A further advantageous embodiment of the invention consists in that all the sections of the winding are wound and are symmetrical both on the tooth feet and on the tooth heads; in this case, all the coils are wound in the same sense on the stator heads and the stator feet.
Exemplary embodiments of the invention will be described in principle in the following text, with reference to the drawings.